Generally, there are various methods for monitoring and analyzing muscle condition and/or performance. Often, such muscle monitoring and analysis involves some form of myometry, which measures the strength of a muscle by measuring the force that the muscle can generate. For an example of myometry, a user squeezes a device which in turn measures and transmits force information back to a computer, and the computer computes a force/time curve. The measurement is usually via electronic components, and thereby can be referred to as electromyometry. These electronic devices are typically fully wired systems that require immediate proximity to a computer, and which are designed to be operated by physicians or clinicians in appropriate controlled settings.
Surface electromyometry (sEMG) is a type of myometry that uses surface sensors to obtain information about the functionality of one or more muscles during a muscular activity. The sEMG assessments can be sorted into three general groups of muscle activity: static muscle activity, dynamic muscle activity, or combination of static and dynamic muscle activities. The different muscle activity paradigms can be useful for different muscle assessments.
A static muscle activity may occur with no load (i.e. sitting) or with an isometric load (no movement of limb). Static muscle activity evaluation can include observation of the rectified amplitude of the sEMG data. The static muscle activity evaluation can be useful for a specific muscle or muscle group or as a comparison to other muscles or muscle groups. Absolute levels of the sEMG data can be monitored through root mean square of the sEMG amplitude (e.g., RMS sEMG amplitude), and abnormally large values of the RMS sEMG can be identified or determined. Rhythmic contraction patterns of the muscle or muscle groups can be identified or determined, and may also be based on rectified amplitude. During an isometric loading protocol, a user can exert an amount of force while keeping the limb fixed in a single position. Usually, the force exerted is measured as a fixed percentage of Maximum Voluntary Contraction (MVC). Then, the median frequency (MF) or mean power frequency (MPF) can be measured or determined by observing or analyzing the frequency spectrum of the sEMG. In this manner, the fatigue level of the muscles can be established, and the point at which fatigue begins to occur may be identified.
Dynamic muscle activity evaluations can ascertain relationships between sEMG amplitude and force, which have been shown to be “curvilinear”, or non-linear at the extremes of the force range (e.g., very little force, or a lot of force) and essentially linear for the majority of the force/amplitude relationship. Evaluating that relationship is useful for dynamic muscle activity sEMG evaluation. Methods for implementing dynamic muscle activity evaluations can include incrementally increasing the force exerted by the muscle by way of a machine that measures force, and measuring the sEMG amplitude of the muscle activity that is associated with various force levels. Dynamic muscle activity evaluations can be used in the evaluation of torque and paralysis. There are dynamic muscle activity evaluation methods for: muscle imbalance, trigger points, cocontractions, and fasciculations.
However, the abovementioned muscle assessment methods can be used to assess a variety of pathologies and physiological states which may correspond to (or attempt to correspond to) clinical and/or medical conditions. These methods have typically been designed to be performed by specialists (e.g., MD, chiropractor, physical therapist, etc.). However, these muscle assessment methods are usually restricted to controlled settings in the presence of these specialists. Thus, there is not a way for a common person to implement muscular assessment on their own. Therefore, there remains a need to bring the ability to implement muscle assessment to the masses.